Mechanical foaming device



Aug. 26, 1958 A. J. HURSTQ MECHANICAL FOAMING DEVICE Filed Aug. 9, 1956 INVENTOR. Hlf'erd (ZHUP-S'Z Fawn/M7 MM Affy.

MECHANICAL FOAMING DEVICE Alfred J. Hurst, Santa Rosa, Califl, assignor to Ply-Bord lino, Healdsburg, Califl, a corporation of California Application August 9, 1956, Serial No. 603,148

3 Claims. (Cl. 259-8) This invention relates to a device for aerating or foaming a liquid by mixing additional quantities of air into it and is particularly useful in producing the conditioned adhesive employed in the manufacture of composite products, as disclosed in my copending application Serial No. 574,974, filed March 30, 1956, entitled Production of Coated Wood Products. The present invention relates to the mechanical construction of a device for foaming adhesives and the like prior to use in the manufacture of composite products.

The object of the invention is to provide an inexpensive, reliable device whereby air will be mixed with the liquid and when the foamed mixture reaches the desired consistency or viscosity it runs out of the container in which it is being agitated.

Generally, this object is accomplished by feeding the unfoamed liquid into a container having inwardly sloped walls and in which an agitating device is positioned for operation. The container is partially filled with liquid and as the agitating device operates, air is beaten into the liquid which rises along the side walls of the container to an outlet opening from which it is conducted to a holding tank prior to use, i. e. foamed glue for use in the manufacture of paper covered veneer.

Fig. 1 is a side elevation in section of the device according to the invention;

Fig. 2 is a top plan view of the device; and

Fig. 3 is a top plan view of the agitating mechanism.

Referring to the drawings, is a frusto conically shaped container having inwardly sloped walls 11 and 12. An opening 13 is provided in the bottom of container 10 to which is connected a T fitting 14. Pipe 15 and valve 16 control the infeed of unfoamed liquid. Valve 17 is opened and valve 16 closed when it is desired to clean out the contents of the container. Approximately two thirds of the way up from the bottom of the container, a discharge opening 18 is provided in the side walls. Suitable pipe connections 18' extend from opening 13 to a holding tank 19 wherein foamed glue or the like may be stored prior to use. Piping 20 serves to discharge the foamed glue from tank 19. A lid 21 extends over the top of container 10. An inlet hole 22 in lid 21 has a valve 23 and a hose connection 24 connected thereto for the purpose of introducing washout liquid into the container.

A centrally disposed hole 25 in lid 21 has passing therethrough a shaft 26 which is connected to a driving mechanism such as a motor 27 capable of rotating shaft 26 counterclockwise at a speed ranging from about 12,000 to 16,000 R. P. M. Ball bearing collars 28 surround shaft 26 along its length outside of container 10.

Referring to Fig. 3, two pairs of blades or vanes 29 and 30 are mounted at 90 to each other on the end of shaft 26 opposite the motor. The shaft extends almost to the bottom of the container and about a half inch clearance between blades 30 and the bottom of the container has been found to be satisfactory. Blades 29 are approximately twice as long as blades 30 while being hired States atent about the same width. The blades are mounted on the end of shaft 26 approximately half an inch apart in the vertical plane with blades 29 on top and blades 30 below.

Shaft 26 and pairs of blades 20 and 30 constitute an agitating means for the device. Blades, 29 making up the upper blade means in the device are inclined so that on rotation of shaft 26, the lower edges of the blades are the leading edges and the upper edges of the blades are the trailing edges. Blades 30 making up the lower 3 blade means in the device are inclined so that on rotation of shaft 26, the upper edges of the blades are the leading edges and the lower edges of the blades are the trailing edges. Thus, the blades of one set are pitched oppositely to the blades of the other set, and liquid is impelled by the sets of blades in opposite directions. Blades 29, the larger and uppermost set of blades, forces material upwardly in the container. Each upper blade 29, since it is larger than each lower blade 30, impels liquid upwardly with a force greater than the force with which liquid is impelled downwardly by a lower blade.

By way of example of my invention, I have found that in order to produce a flow of foamed liquid at the rate of one and a half gallons per minute, a container having the following dimensions is satisfactory: height from bottom to toptwelve inches; distance between inside walls at bottom of containerseven inches; distance between walls at outlet opening nine inches; diameter of outlet opening-about one inch; diameter of inlet openingabout three quarters of an inch and an inlet flow at the rate of approximately two quarts per minute of unfoamed liquid.

The device may be operated as follows to produce adhesive useful for the purposes disclosed in said copending application: the container is filled to approximately half its capacity and shaft 26 is rotated by motor 27 to about 14,000 R. P. M. Unfoamed liquid adhesive at room temperature (80 F.) is continually admitted through pipe 15 at the rate of approximately two quarts per minute. Valve 16 is regulated to permit inflow of liquid at the desired rate. Air is beaten into the adhesive by the action of blades 29 and 30. As the adhesive becomes foamy it rises up side walls 11 of the container until it reaches opening 18 whereupon it runs out of the container through pipe 18 into holding tank 19.

Although the present invention has been described in connection with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as will be appreciated by those skilled in the art. All such modifications and variations are intended to come within the scope of the invention as defined in the appended claims.

I claim:

1. A mechanical foamer for producing continuously foamed liquid comprising a container having a top, a bottom, side walls sloping inwardly from top to bottom, an inlet in the bottom of the container for admitting unfoamed liquid, a lid over the top of the container, an inlet in the lid for admitting wash-out liquid, an agitator shaft passing through approximately the center of the lid and extending to a point closely adjacent the bottom, agitator means for agitating the liquid aflixed to a lower portion of said agitator shaft, said agitator means having two sets of blades fastened adjacent the lower end of the agitator shaft, the top set of blades being pitched to impel liquid upwardly in the container on rotation of said shaft and the bottom set of blades being pitched to impel liquid downwardly in the container on rotation of said shaft, motor means for driving said shaft, an outlet opening in an upper portion of a side wall of the container positioned above said agitator means, a holding tank positioned outside the container, pipe connections 3, from said outlet opening to the holding tank, whereby when liquid is placed in the container and the agitator shaft driven the liquid is foamed and rises in the container to flow out of the container through the outlet opening to the holding tank.

2. A mechanical foamer for producing continuously foamed liquid comprising a container having side walls and a bottom wall for holding liquid, said side walls sloping inwardly from top to bottom, inlet means at the base of said container for introducing unfoamed liquid into said container, an outlet for said container spaced vertically above said inlet means for removing foamed liquid, an agitator shaft carried vertically and approximately centrally in said container and having an upper and a lower blade means affixed to said shaft, drive means for rotating said shaft in a given direction, said upper and lower blade means being spaced on said shaft below said outlet, each blade means having at least one agitator blade, said upper blade means impelling liquid upwardly in said container on rotation of said shaft, said lower blade means impelling liquid downwardly in said container on rotation of said shaft, said upper blade means being configured relative to said lower blade means whereby liquid is impelled upwardly with a force greater than the force with which liquid is impelled downwardly by said lower blade means, a holding tank positioned outside the container, and pipe connections from said outlet to said holding tank, whereby when liquid is placed in the container and the agitator shaft driven the liquid is foamed and rises in the container to flow out of the container through the outlet to the holding tank.

3. The foamer of claim 2 wherein said upper and lower blade means each have the same number of agitator blades, and wherein the blades of said upper blade means are larger than the blades of said lower blade means.

References Cited in the file of this patent UNITED STATES PATENTS 201,900 Whitney Apr. 2, 1878 388,724 Schumm Aug. 28, 1888 1,156,606 Lawrie Oct. 12, 1915 1,792,190 dos Santos Feb. 10, 1931 2,011,483 Hansen Aug. 13, 1935 2,146,566 Daman Feb. 7, 1939 2,387,488 Acken et a1 Oct. 23, 1945 2,448,927 Fischer Sept. 7, 1948 UNITED STATES PATENT OFFICE IER'HFICATE @F fiQRREETEON Alferd J, Hurst It is hereby certified that error appears in the above numbered patent'requiring correction and that the said Letters Patent should read as corrected below,

In the grant line 1, and in the heading to the printed specification, line 3, name of inventor, for "Alfred J" Hurst", each occurrence, read Alferd J Hurst Signed and sealed this 25th day of November 1958,,

SEAL) fittest:

KARL H, AXLINE ROBERT C WATSON Atteeting Officer Commissioner of Patents 

